The European Central Bank’s asset purchases last month slowed to the weakest since quantitative easing started in March as liquidity dried up during Europe’s summer holiday period.

Holdings of government and agency debt, covered bonds and asset-backed securities rose by 51.6 billion euros ($57.6 billion) in August, the ECB said on Monday. The increase compares with 61 billion euros in July and 63 billion euros in each of May and June.

While the Frankfurt-based central bank intends to buy 60 billion euros a month of debt through September 2016 to revive euro-area inflation, it has repeatedly said the program can be adjusted to take account of market conditions. Purchases were frontloaded before the summer and ECB President Mario Draghi has signaled that the same strategy may be used before December.

The program is “still on track” despite August’s decline, said Kim Liu, a fixed-income strategist at ABN Amro Bank NV in Amsterdam. “Last week’s purchases are indicating that the summer break has ended for the ECB.”

In weekly data also published Monday, the ECB said holdings of public-sector debt rose by 11.9 billion euros in the period ended Sept. 4 to total 301.4 billion euros. Holdings under its current covered-bond program climbed by 1.1 billion euros to 112.2 billion euros. ABS holdings increased by 382 million euros to 11.5 billion euros.

Draghi said last week that the size, composition and duration of the QE program can be altered if needed for the ECB to reach its goal of returning medium-term inflation to just under 2 percent. Consumer prices rose an annual 0.2 percent in August and the euro-area recovery risks being undermined by a China-led slowdown in global growth, spurring speculation that the ECB may need to ease monetary policy further.

The ECB bought 42.8 billion euros of government and agency debt in August, the data on its website showed. Purchases of covered bonds were 7.5 billion euros and those of ABS were 1.3 billion euros.