European stocks posted minor gains Friday before the release of a widely watched jobs report from the U.S., and as investors monitored a ramp-up in tensions in Ukraine.

The Stoxx Europe 600 was up less than 1 point 338.64, but remained in line for a weekly advance of 1.5%.

Investors later in the session will receive the April jobs report from the U.S., the world's biggest economy. Economists polled by MarketWatch expect a net increase of 215,000 jobs, which would mark the biggest increase since a 274,000 gain in November. The unemployment rate is expected to fall to 6.6% from 6.7%. The nonfarm-payrolls report should be released at 1.30 p.m. in London, or 8.30 a.m. Eastern Time.

Ukraine has launched a "large-scale operation" to take back control of the city Slovyansk. Russian President Vladimir Putin on Thursday called on Ukraine to withdraw its military forces from southeast Ukraine, which would effectively give pro-Russian forces control of the area. Meanwhile, Ukraine's acting President Oleksandr Turchynov has said a military draft will renewed.

Russian equities pulled lower, dragging the blue-chip MICEX Index down 0.3% to 4,474.25, and the RTS index down by 0.9%.

The heightened tensions between Kiev and Moscow came ahead of a three-day weekend in the U.K. and Ireland that will see trading shuttered on Monday.

The U.K.'s FTSE 100 was up 0.1% at 6,816.68, topped by spikes of more than 8% each in shares of Royal Bank of Scotland Group PLC and InterContinental Hotels Group

The 80% state-owned bank said first-quarter profit jumped to 1.2 billion pounds ($2.02 billion), while InterContinental Hotels , whose brands include Holiday Inn and Crowne Plaza, said it plans to distribute $750 million to shareholders through a special dividend.

But AstraZeneca PLC (AZN) shares fell 0.5% as the British drug maker rejected a sweetened merger offer from Pfizer Inc. (PFE) , saying the higher bid of GBP50 a share ($84.46) was "inadequate," and would dramatically dilute AstraZeneca shareholders' exposure to its "rapidly progressing" pipeline.

"As such, the board has no hesitation in rejecting the proposal," said AstraZeneca's Chairman Leif Johansson in a statement. AstraZeneca shares did manage to recover from a deeper loss of about 0.9% that came just after the statement was released.

Elsewhere in the drug sector, Germany's Bayer AG is close to a takeover of Merck & Co. Inc.'s (MRK) consumer-healthcare unit in a deal valued at $14 billion, Bloomberg reported on Friday. Bayer shares were up 0.7% in Frankfurt. A representative from Bayer declined to comment on the report, while a spokesperson from Merck wasn't immediately available to comment.

Germany's DAX 30 , however, was off 4 points at 9,600.27, and France's CAC 40 shed 0.4% to 4,468.99, after being closed Thursday for the May Day holiday. Those indexes were on track for weekly gains of 2.1% and 0.6%, respectively.

There was overall improvement in the euro-zone's manufacturing sector in April, with recovery in the area becoming broader-based, according to the final reading of Markit's purchasing managers index. It rose to 53.4 from 53.0 in March, slightly higher than an initial reading of 53.3.