Robert Slentz sued the City of Republic, Missouri, and Interim City Administrator Greg D. Chadwell alleging that the defendants violated his rights under the Family and Medical Leave Act (“FMLA”). The district court1 granted the defendants’ motion for summary judgment. We affirm.
I. Background
Robert Slentz, a full-time police officer for the City of Republic, Missouri, injured his shoulder while off duty. Slentz took sick leave due to the injury and eventually *1010underwent corrective surgery on his shoulder. Following his surgery, Slentz received a letter from the City designating his sick leave as FMLA leave based upon the City’s Personnel Policy. The letter also informed Slentz that, among other things, he must submit a fitness-for-duty certificate from his physician prior to being restored to employment.
By a second letter, the City informed Slentz of the approaching expiration date for his FMLA leave and reminded him that he would need to provide a fitness-for-duty certificate at least one day prior to returning to work. The letter stated further that if such a certificate were not provided, Slentz would be expected to resign at the expiration of his FMLA leave. Unfortunately, Slentz’s physician declined to certify Slentz as fit for duty until he had recuperated — several weeks after the expiration of his leave. Accordingly, Slentz submitted his letter of resignation.
Slentz sued, alleging that the defendants wrongfully interfered with his rights under the FMLA. The district court'granted the defendants’ summary judgment motion. The court held that it was permissible to run sick leave and FMLA leave concurrently, that Slentz was given proper notice, and that the defendants did not otherwise wrongfully interfere with Slentz’s exercise of FMLA leave. Finding no error, we affirm.
II. Discussion
A. Concurrent Leave
Slentz contends that the City violated his FMLA rights by extending him only twelve weeks of leave despite his having more than twelve weeks of accrued sick leave. We disagree. The FMLA provides that an “eligible employee” — e.g., one with a “serious health condition that makes the employee unable to perform the functions of the position of such employee”— “shall be entitled to a total of 12 workweeks of leave during any 12-month period.” 29 U.S.C. § 2612(a)(1). The Act grants an employer the power to require an employee to substitute any accrued sick leave for leave provided under the FMLA. § 2612(d)(2)(B). An employer may permit an employee to use FMLA leave and sick leave sequentially or may require that the two run concurrently. Strickland v. Water Works & Sewer Bd. of City of Birmingham, 239 F.3d 1199, 1205 (11th Cir.2001); see 29 C.F.R. § 825.207(f) (“If neither the employee nor the employer elects to substitute paid leave for unpaid FMLA leave ... the employee will remain entitled to all the paid leave which is earned or accrued under the terms of the employer’s plan.”).
In this case, the City elected to run Slentz’s FMLA leave concurrently with his accrued sick leave2 as authorized under the FMLA. Id. A contrary result “would unduly and unfairly burden employers.” Strickland, 239 F.3d at 1206. “[T]he FMLA was intended only to be a statute that provided a minimum labor standard; an assurance that employers would provide employees with twelve weeks of leave every year.” Ragsdale v. Wolverine Worldwide, Inc., 218 F.3d 933, 939 (8th Cir.2000), aff'd 535 U.S. 81, 122 S.Ct. 1155, 152 L.Ed.2d 167 (2002). “Under the FMLA, twelve weeks of leave is both the minimum the employer must provide and the maximum that the statute requires.” Ragsdale, 218 F.3d at 938; accord Strickland, 239 F.3d at 1206 (“To *1011balance the needs of employers and sick employees, Congress intended that the FMLA provide employees with a minimum entitlement of 12 weeks of leave, while protecting employers against employees tacking their FMLA entitlement on to any paid leave benefit offered by the employer.”). Consequently, we affirm the district court and hold that there was no violation of Slentz’s rights under the FMLA.
B. Estoppel
Slentz also argues that the City’s representations to him in its initial notice letter estops the City from claiming that he was limited to twelve total weeks of leave. The letter, in relevant part, read:
Family Medical Leave will begin on January 30, 2003, and is expected to continue until you are released from your doctor’s care.
Except as explained below, you have a right under the FMLA for up to twelve weeks of unpaid leave in a twelve month period....
Pointing to the first sentence above, Slentz asserts that (1) the City knew when it sent the letter that Slentz was expected to be off work until approximately May 17, 2003; and (2) that he had accrued unused sick and vacation leave that would have covered him beyond May 17, 2003.3 Slentz contends that his reliance on this sentence presents a genuine issue of material fact, making the grant of summary judgment improper. However, the City correctly points out in its brief, as did the district court in its decision, that the very next sentence of that letter undermines Slentz’s argument because it unambiguously states that Slentz was entitled to a maximum of twelve weeks of FMLA leave.
For legal support, Slentz cites Duty v. Norton-Alcoa Proppants, 293 F.3d 481, 493 (8th Cir.2002). However Duty is'distinguishable because it dealt with an employer’s letter that informed the employee that his entire 34-week sick leave qualified under the FMLA. In Duty, this court held that the district court did not abuse its discretion in applying equitable estoppel to prevent an employer from claiming that the employee’s leave was confined to the twelve weeks actually afforded by the FMLA. Id. at 494. The court reasoned that the letter explicitly guaranteed the employee 34 weeks of leave and that the facts indicated that the employee had relied on this representation. Id. By contrast, the initial letter to Slentz did not explicitly guarantee'him a specific amount of leave or leave until a specific date but instead assured him twelve weeks of FMLA leave. In addition, Slentz could not have relied on the City’s letter in electing surgery because his shoulder surgery was complete when he received the letter. Therefore, we hold that the City was not estopped from limiting 'Slentz to twelve weeks of leave by its notice letter.
C. Record Keeping
Slentz next posits that summary judgment was improper because the City has not given Slentz records required by 29 C.F.R. § 825.500. Slentz contends that the failure to give him these records creates a genuine issue of material fact as to whether his leave was designated and counted as FMLA leave. This argument fails for two reasons. First, § 825.500 only requires the submission of records when specifically requested by a Department of Labor official. § 825.500(a) (“These regulations establish no requirement for the submission of any records unless specifically requested by a Departmental official.”). Second, the City’s initial letter clearly informed Slentz that the City considered the leave to be FMLA leave. 29 C.F.R. §' 825.208(a)(stating that an em*1012ployer bears the responsibility to “designate leave, paid or unpaid, as FMLA-quali-fying, and to give notice of the designation to the employee.... ”). In sum, Slentz’s record keeping argument lacks merit.
We hold that the City was permitted to run Slentz’s sick leave concurrent with his FMLA leave, that the City was not es-topped by its February letter, and that the City was not required to submit any records to Slentz pursuant to § 825.500. Therefore, we affirm the district court’s grant of summary judgment.
. The Honorable Richard E. Dorr, United States District Judge for the Western District of Missouri.
. Section 12.5 of the City of Republic Personnel Policy, entitled "Sick and Emergency Leave," states as follows:
"In all cases where applicable, sick/emergency leave will be subject to and designated by the City of Republic as FMLA leave and counted against an eligible employee's FMLA leave entitlement."
. Slentz's twelve weeks of leave expired on April 24, 2003.